1. Field of the Invention
The present invention relates to a production method and a production apparatus for a magnetic recording medium.
2. Description of the Related Art
In recent years, magnetic recording media such as hard disks and the like have undergone significant increases in recording density as a result of improvements including miniaturization of the magnetic particles that make up the recording layer, development of new materials, and miniaturization of head processing technology, and it is envisaged that the future will bring further increases in recording density.
However, increasing the recording density by conventional improvement techniques such as miniaturization of the magnetic particles has now reached its limit, and discrete type magnetic recording media, in which a continuous recording layer is partitioned into a plurality of partitioned recording elements, and a non-magnetic body is then used to fill the grooves between these partitioned recording elements, have been proposed (for example, see Japanese Patent Laid-Open Publication No. Hei 9-97419) as an example of magnetic recording media which will enable further improvements in recording density.
Dry etching techniques such as reactive ion etching are examples of processing techniques that can be used to create minute partitions within a continuous recording layer (for example, see Japanese Patent Laid-Open Publication No. Hei 12-322710).
Furthermore, embedding techniques that utilize wet processes such as those used in the field of semiconductor production (for example, see Japanese Patent Laid-Open Publication No. Hei 13-323381) can be used to achieve the non-magnetic filling described above.
If level differences occur between the surfaces of the partitioned recording elements and the non-magnetic body then problems such as instability of the head flying movement and the accumulation of foreign matter can arise, and consequently the surface of the partitioned recording elements and the non-magnetic body are preferably smoothed. This smoothing operation can also be conducted using processing techniques used in the field of semiconductor production, such as CMP (Chemical Mechanical Polishing) techniques based on wet processes.
In addition, a wet cleaning technique used in semiconductor production (for example, see Japanese Patent Laid-Open Publication No. Hei 12-091290) can be used for removing foreign matter from the surface of the partitioned recording elements.
However, if the type of dry etching used in a semiconductor production process is used, as is, for processing a continuous recording layer, then sections of the partitioned recording elements are prone to problems of deterioration such as oxidation and corrosion. Deterioration of the partitioned recording elements may also occur over a period of time following production. In addition, the action of solvents and the like during other wet processes such as cleaning can also cause problems such as oxidation and corrosion within some sections of the partitioned recording elements. Another problem arises in that the use of wet processes increases the likelihood of contamination of the surface of the partitioned recording elements with foreign matter. These problems of deterioration and contamination of the partitioned recording elements can cause a loss of precision in the recording and reading of information.
Furthermore, combining dry processes and wet processes creates additional problems in that transportation of work (intermediates products of the magnetic recording medium) becomes more difficult, and production efficiency deteriorates.
In other words, because magnetic recording media have unique problems, including the fact that the magnetic material tends to be prone to oxidation, the use of processing techniques that are effective within other fields, such as semiconductor production, during the production of magnetic recording media results in a variety of problems such as oxidation of the magnetic material, and accordingly producing discrete type magnetic recording media with good efficiency, while preventing deterioration of the partitioned recording elements, has proven to be very difficult.